Combination of benzotriazole with other materials as EP agents for lubricants

ABSTRACT

The extreme pressure property of a lubricant is remarkably improved by adding to the lubricant a mixture of sulfurized alkylene monomer, dihydrocarbyl phosphonate and benzotriazole.

United States Patent 11 Olszewski [451 Nov. 11,1975

[ COMBINATION OF BENZOTRIAZOLE WITH OTHER MATERIALS AS EP AGENTS FORLUBRICANTS [75] Inventor: William Frank Olszewski, Cherry Hill. NJ.

[73] Assignee: Mobil Oil Corporation, New, York,

[22] Filed: Oct. 29, 1974 211 Appl. No.: 518,669

UNITED STATES PATENTS 3.553.131 l/l97l l-lepplewhite et al 252/46.7

Hendrick son 252/46] Nebzydoski et al. 252/46] ll/l97l ll/l974 PrimaryE.\'uminerDelbert E. Gantz Assistant Exmniner-I. Vaughn Attorney, Agent,or Firm-Charles A. Huggett; Raymond W. Barclay; Claude E. Setliff [57]ABSTRACT The extreme pressure property of a lubricant is remarkablyimproved by adding to the lubricant a mixture of sulfurized alkylenemonomer. dihydrocarbyl phosphonate and benzotriazole.

9 Claims, No Drawings COMBINATION OF BENZOTRIAZOLE WITH OTHER MATERIALSAS EP AGENTS FOR LUBRICANTS BACKGROUND OF THE INVENTION lubricantscontaining a mixture ofa sulfurized alkylene monomer, dihydrocarbylphosphonate and benzotriazole.

2. Summary of the Prior Art U.S. Pat. No. 3,115,465 deals withcombinations of phosphorus compounds and hindered phenols for inhibitionof oxidation of organic compositions. U.S. Pat. No. 3,471,404 teaches aprocess for making sulfurized olefins and discloses them to be useful asloan carrying additives. It is known, in accordance with U.S. Pat. No.3,652,41 1 that benzotriazole can be mixed with other materials such asa phenol, an amine, a polyhydroxyquinone, an amine salt and an organicphosphite to produce an antioxidant for polyglycol base lubricants.Further, U.S. Pat. No. 3,597;353 teaches the use of benzotriazole as acopper 'deactivator in an anti-freeze solution. However, it will beapparent fromthe remaining disclosure that these patents do not discloseor suggest the inventiondisclosed and claimed herein.

SUMMARY OF THE INVENTION The invention provides a lubricant compositioncomprising a mineral or a synthetic hydrocarbon or synthetic esterbaselubricant'and an additive mixture comprising (1) a dihydrocarbylphosphonate having from 1 to carbon atoms,(2 a sulfurized'alkylenemonomer, wherein alkylene has from 2 to 6 carbon atoms andbenzotriazole? DESCRIPTION OF SPECIFIC EMBODIMENTS Thedi(organo)phosphonates used in this invention have the structure whereinR and R are individually alkyl or alkenyl from I to 20 carbon atoms andmay have the same number of carbon atoms or a different number. Thephosphonates used in this invention may be produced by known methods ofsynthesis The second co-additivefor the compositions of this inventionmay be designated as an active sulfur compound. The compounds of thisclass consist of sulfurized hydrocarbon monomers having up to 65%sulfur. Encompassed in this class are those compounds wherein the sulfuris loosely-bound, and the non-corrosive or firmly-bound sulfurcompounds.

The preferred example of the sulfur additive used in this invention arethe polysulfurized alkylene hydrocarbon monomers, particularly thosederived from olefins having from 2 to 6 carbon atoms. Suitable examplesof such organic polysulfides are the polysulfides of ethylene,propylene, butylene, amylene, and the like. Sulfurized alkylenecompounds, such as sulfurized isobutylene containing from about 30% toabout 65% sulfur,

2 and preferably from 35% to 50% sulfur, are used herein. g

The preferred sulfurized alkylene compounds may be prepared by knownmeans. One of the suitable routes for obtaining this additive is throughthe reaction of a mercaptan with a sulfur halide to form anorganosulfenyl halide. This halide is then reacted with an olefin,whereby the sulfur atoms are added to the carbon atoms on either side ofthe double bond. The product so formed is a thioethyl halide. lFurtherreaction of this compound with a sulfur-containing metal or ammoniumsalt, such as a metal sulfide, adds another sulfur atom to the product.Another means of obtaining polysulfurized alkylene compounds involvesreacting the sulfur halide, such as sulfur monocliloride, with an excessof olefin, such as isobutylene. This product is reacted with an alkalimetal sulfide: in the presence of free sulfur. The resulting product isthen neutralized with an inorganic base, such as sodium hydroxide. SeeU.S. Pat. No. 3,471,404. In these reactions, the use of butylene as theolefin is preferred. The products contain a high percent of sulfur whichhas been found to be non-corrosive to metal parts of engines.

The compositions of this invention are effective in fluid compositionsin which the lubricant base is a pctroleum product, suchas a minerallubricating oil, or a synthetic fluid. Such synthetic oils ashydrocarbon fluids derived from either long chain alkanes or olefinpolymers, ester lubricants obtained from polyhydric alcohols andmonocarboxylic acids or monohydric alcohols and dicarboxylic acids maybe used as the base medium for this invention.

The additive concentration may vary from about 0.02 to about 10.0 7c foreach of the phosphonate and sulfurized alkylene additives.Preferably,the range is from 0.10 to 4.0 by weight of lubricant. Optimumperformance characteristics are evidenced when the fluid compositioncontains from about 0.02 to 0.50 and especially 0.10 phosphorus and fromabout 0.50 to 10.0 and especially 2.0 sulfur.

The third ingredient of the additive mixture is benzotriazole, and it isused to the extent of from about 0.005% to about 1.0% of the lubricant.Benzotriazole has an entirely unexpected effect on the combination ofphosphonate and sulfurized hydrocarbon. As will be demonstrated below,when known E.P. agents are added to base oil containing the phosphonateand sulfurized hydrocarbon, no increase in EP properties (over thoseshown by the additives already present) is noted.

EVALUATION OF INVENTION The base oil used was an SAE mineral oillubricant containing an additive package comprising dibutyl phosphonate[(C H O) POH] and sulfurized isobutylene containing about 45% sulfur(prepared substantially in accordance with U.S. Pat. No. 3,471,404). Tothis lubricant composition were added several known E.P. agents invarying concentrations. Then benzotriazole was added in place of theknown E.P. agents. The resulting composition, in each case, was testedin the Timken Load Test.

This test is a known test used to determine the load carrying propertiesof additives in lubricating oil compositions. The test is conducted byplacing a steel test cup on a shaft which can be rotated at 800 rpm.Just below the cup and in contact with it is a small stationary steelblock. A load is placed on these parts by 3 means of a lever arm whichpushes the block upwards against the rotating cup, which acts as aroller bearing, while the lubricant flows between the two surfaces. Theload is gradually increased at 10-minute intervals until failure occurs.Failure is determined by visual inspection during the running period.Load usually varies from to 80 pounds. The load for a pass result is thehighest load which does not produce scoring of the contacting testsurfaces.

The table below summarizes the results.

TIM KEN TEST Composition Pass Load, lbs.

Base oil 45 Base oil l.0'7( sulfurized polyisobutylene 45 Base oil l.0%sulfurized sperm oil substitute* 45 Base oil l.()% chlorinated wax (40%chlorine) 40 Base oil 0.5% octyl acid phosphonate 40 Base oil 0.3%benzotriazole 70 Base oil 0.5% benzotriazole 70 Base oil 0.005%benzotriazole 60 *sulfurized vegetable oil containing sulfur It isapparent from this data that there was either no change in the pass loador such load actually decreased when conventional E.P. agents were addedto the base oil (containing phosphonate and sulfurized hydrocarbon).Apparent also is the fact that when as little as 0.005% benzotriazolewas added to the same system, there was an increase of more than l5pounds at the 0.005% concentration and more than 25 pounds at the 0.05%and 0.3% levels. Such a result was entirely unexpected.

The above table is presented merely for the purposes of illustration andis not intended to limit the scope of the invention.

I claim:

l. A lubricant composition containing a major proportion of a mineraloil, a synthetic hydrocarbon fluid, a synthetic ester lubricating oil ora grease made therefrom and an extreme pressure amount of the additivemixture comprising a dihydrocarbyl phosphonate. a sulfurized alkylenemonomer and benzotriazole.

2. The composition of claim I wherein the phosphonate has the formulawherein R and R are the same or different and are individually selectedfrom the group consisting of alkyl and alkylene having from I to 20carbon atoms.

3. The composition of claim 1 wherein the sulfurized alkylene is asulfurized olefin having 2 to 6 carbon atoms.

4. The composition of claim 3 wherein the sulfurized olefin containsfrom about 30 to about sulfur.

5. The composition of claim 4 wherein the sulfur content is from about30% to about 50%.

6. The composition of claim 2 wherein R and R are butyl.

7. The composition of claim 3 wherein the sulfurized olefin issulfurized isobutylene.

8. The composition of claim 1 wherein the lubricant is a minerallubricating oil 9. The composition of claim 1 wherein the lubricant is amineral lubricating oil, the dihydrocarbyl phosphonate is dibutylphosphonate and the sulfurized alkylene monomer is sulfurizedisobutylene containing about 45% sulfur.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTEFICATE OF CORRECTIONPATENT NO. 3,919,096

DATED 1 November ll, 1975 IN 1 WILLIAM FRANK oLsZEwsKI It is certifiedthat error appears in the above-identified patent and that said LettersPatent 0 are hereby corrected as shown below:

Column 1, line 18 "loan" should read -load-.

H H Column 1, llne A5 I RO\P/O a B0 H should read RO O.

R'6 H Column 1, line 49 "R and R" should read R and R'-. Column 1, line10 "RO O" P & RO H should read -RO o--.

R'O H Column i, line 15 "R and R" should read -R and R'. Column l, line26 "R and B" should read R and R'-. Column l, line 31 Place period atend of the word "Oil".

Signed and Sealed this eighteenth Day of May 1976 [SEAL] Atresr:

RUTH C. MASON C. MARSHALL DANN T Amuing Officer (ommissimu'r of Patentsand Trademark

1. A LUBRICANT COMPOSITION CONTAINING A MAJOR PROPORTION OF A MINERALOIL, A SYNTHETIC HYDROCARBON FLUID, A SYNTHETIC ESTER LUBRICATING OIL ORA GREASE MADE THEREFROM AND AN EXTREME PRESSURE AMOUNT OF THE ADDITIVECOMPRISING A DIHYDROCARBYL PHOSPHONTE, A SULFURIZED ALKYLENE MONOMER ANDBENZOTRIAZOLE.
 2. The composition of claim 1 wherein the phosphonate hasthe formula
 3. The composition of claim 1 wherein the sulfurizedalkylene is a sulfurized olefin having 2 to 6 carbon atoms.
 4. Thecomposition of claim 3 wherein the sulfurized olefin contains from about30 to about 65% sulfur.
 5. The composition of claim 4 wherein the sulfurcontent is from about 30% to about 50%.
 6. The composition of claim 2wherein R and R'' are butyl.
 7. The composition of claim 3 wherein thesulfurized olefin is sulfurized isobutylene.
 8. The composition of claim1 wherein the lubricant is a mineral lubricating oil
 9. The compositionof claim 1 wherein the lubricant is a mineral lubricating oil, thedihydrocarbyl phosphonate is dibutyl phosphonate and the sulfurizedalkylene monomer is sulfurized isobutylene containing about 45% sulfur.